To regulate electromagnetic (EM) radiation and conduction of electronic devices, regulatory limits have been mandated by governmental agencies all over the world, such as the FCC in the U.S. and the CISPR in the E.U. In order to comply with these regulations, different techniques to mitigate EM radiation are applied to a product, ranging from board layout to filtering to shielding. One of the most common techniques to reduce EM interference (EMI) is to create some sort of metallic enclosure around the product, e.g., a Faraday cage. Such EMI reduction techniques may be difficult to deploy in a system that uses wireless charging.
A basic wireless charging system may include a wireless power transmitter unit (PTU) and a wireless power receiving unit (PRU). For example, a PTU may include a transmit (Tx) coil, and a PRU may include a receive (Rx) coil. Magnetic resonance wireless charging may employ a magnetic coupling between the Tx coil and the Rx coil. When a wireless charging module is integrated in a product, the Faraday cage approach to EMI reduction may interfere with the wireless charging.
The same numbers are used throughout the disclosure and the figures to reference like components and features. Numbers in the 100 series refer to features originally found in FIG. 1; numbers in the 200 series refer to features originally found in FIG. 2; and so on.